Method for increasing stability of rubbery polymer reaction products and resulting compositions



Patented Oct. 6, 1953 UNITED STATES PATENT OFFICE METHOD: FOR INCREASINGSTABILITY OF RUBBERY POLYMER REACTION PROD- UCTS AND RESULTINGCOMPOSITIONS Johan Michaef Goppel, Gottfried Ernst" Rum.-

scheidt, and Johannes Thomas. Hackm'a'nn,

Amsterdam, Netherlands,v assignors to Shell Development Gompan acorporation ofDelat y, San. Francisco, Cali-f., vare No Drawing.Application April 26, 1949, Serial N0. 89,802. In the'Netherlands-MayI8, 1948' 13 Claims 1 This invention: is directed; to a process. for thestabilizationof products formed. on reactingrinorganic acidifying.compounds with rubbery polymers comprising high. molecular Weight,vpolyunsaturated compounds; The invention also relates to the resultingstabilized: reaction: products.-

The term. high molecular weight, polyunsaturated. compound, as. employedherein, embraces those compounds having'a molecular weightofi at least5,000 and which contain a plurality of uni- J saturated linkages in. themolecule; These com pounds: are. either polymers a. of organic compoundscontaining a plurality of unsaturated: linkages in the molecule;- or arecopolymers of such multiple.- unsaturated compounds with otherunsaturated organic: compounds of one type or another; Ihe term includesthe various natural. rubbers such as latex, crepe, sheet,- caoutchouc;gutta percha, balata, and cyclorubbers; as well asunsaturated syntheticrubbers; ymers of high molecular weight are the polymeri zation productsof butadiene and those of its homologues and derivatives, as, forexample, methyl butadiene polymers, dimethyl butadiene polymers,pentadiene polymers, and chloroprene polymers (neoprene syntheticrubber). Representativez copolymers of high molecular weight which comewithin the term are those formed from buta'diene, its. homologues andderivatives, with: other unsaturated organic compounds. Among the latterarethe-acetyleneseas vinyl acetyl'ene, the olefins, as isobutylenewhich: copol ymerizes with butadiene to: form Butyl: synthetic rubber;the vinyls,- asvinyl: chloride, acrylic acid,

acryl'onitri-le- (which polymerizes with butadiene to form thesyntheticrubber Buna-N methacrylicacid, and styrene; the latter compoundpolymerizing with butadiene to: form the syn.- theticrubber Buna S; aswell asth'e vinyl esters andvarious unsaturated al'dehydes; ketones andethers, e. g., acrolein,.methyl isopropenyl' ketone, and vinyl ethylether. The above-defined; polyunsaturated; high molecular" weightcompounds, includingboth naturaland synthetic rubbers, may: properly:be: termed high. molecular weight polymers of dier ie hydrocarb'ons', orpreferably, rubbery polymers" of at least one compound. se:- lected fromthe group consisting of the: conjugate'd diolefines: and chloroprene'."

As' employed herein, the term: inorganic acidif'ying compound embracesthe various inorganic acids and acid anhydrides whereinthe' acidformingelement ('assul f-ur, nitrogen or phospho'- rus; for example); ifpossessing several valencies, is present, in a valency other than" thehighest Representative synthetic: polthereof. Preferred: acidifyingcompounds are the acid anhydrides, sulfur dioxide, phosphorus trioxideand nitrous trioxide, as well as the acids formed from: thesea-nhydri'des. Other useful acidifying: compounds are: hydrogen sulfide,-hydrochloric acid, hydrobroinic acid, hydroiodic acid, and hydrofluoricacid. The term. does not include such: compounds as! sulfur trioxide.phosphorus pentoxide, nitrogen pentoxide, or their corresponding acids,for in all-. these compounds the acid-forming element. which: is hereeither sulfur; phosphorus or nitrogen-,,. is present in the highest ofseveral possible valencies. Of theva-riou's acidifying: compounds setforthhereim. the most preferred; compound for employment in the presentinvention is sulfur! dioxide.

It. is known that the high molecular weight polyunsaturated compoundslend themselves. well to. the production. ofv various: shapes, includingthose of. a continuous; non-supported nature, as filaments, rods,.stripssheets; and the like: Fur.- thermore, it is know that theproperties of such shapes may" be improved by reacting the unsaturated,,high.molecular weight compound with one or. more: of. the:inorganicacidifying compounds mentioned; above particularly sul-fiurdioxide. The. exact. nature of. reaction is not clearly understood,though; it 18: evident. that. a quantity of the acidifying ingredient istaken. upin one form; or another by the. high: molecular weightreactant. 'llhe ext'en-tlofc this reaction: is normally measured by, andexpressed; in terms. of, the amount. of. acid-forming elementv (sulfur,phosphorus: or. nitrogen,.for; example)- present in the resultingreaction product.

It; has also been possibletc improve: the nature of theforegoingreaction. products by incorporating; therein, normally, prior. to: thereaction. with sulfur dioxide or other acidifying ingredient, a quantityof; a. low molecular weight, unsaturated compound. 'Ehe resulting:reaction product. has.- a number of advantages, chief among which is agreatly improved acceptance for all the commonly employed dyestuffs.Representative unsaturated compounds which may beemployed in thismannor; all'of which hav'ea molecular-weight of below 5,000 arealkadienes such as butadiene' and 1,5 hexadiene; and alkenyl compoundssuch as ally-l alcohol, ally-l chloride; a'llyl acetate;- allylcaprona-te, all yl-= isothiocyanate,- all yl ol'ea'te', and. moreespecially, diallyl compounds such; as: diallyl phthalate and-idiallyli. adipate; IZhe method by which.unsaturatemreactants of bothhigh. and low molecular weight-rv are: utilized; in formingreactionproducts. with; acidifying compounds forms the subject of copendingapplication, Serial No. 15,048, filed March 15, 1948, and reference ishereby made to said application for a more complete description of theinvention there disclosed.

It should be noted that while the high molecular weight, polyunsaturatedcompounds, or mixtures of both high as well as low molecular weightunsaturated compounds, may be reacted with the acidfying compoundWithout prior modification of either reactant, improved results areobtained when the unsaturated compounds are first activated by treatmentwith a hydroperoxide such as decalin hydroperoxide, tetralinhydroperoxide, or ethyl benzene hydroperoxide. Activation methods ofthis nature are disclosed in copending applications, Serial Nos.760,924, filed July 14, 1947, and 788,312, filed November 26, 1947, nowPatent No. 2,558,498, to which applications reference is here made. Theperoxide treatment is also disclosed in copending application Serial No.7

15,048, referred to above, as said activation treatment relates tomixtures of high and low molecular weight unsaturated reactants.

While the reaction products discussed above have proven well adapted formany uses, they have proven particularly useful when formed intofilaments of the type which can be woven into textiles, either alone orin conjunction with fibers of other materials. Thus, filaments producedby spinning a peroxide-activated rubber solution into a sulfurdioxide-containing coagulating bath have a high elementary denier, withgood tensile strength, a relatively high degree of elongation prior torupture, and good flexibility and other characteristics making for easeof working and handling. In view of these many favorable qualities, ithas been highly disappointing to realize that even in the case of thebest reaction products hitherto obtainable, deterioration of thefilament or other shape with age, heating and/ or exposure toultra-violet light is unduly rapid. This deterioration is manifested ina variety of ways, but chiefly in a sharp falling off in tensilestrength and in the degree of permissible stretch prior to rupture. Inmany instances undesirable color changes also ensue. These variouschanges are greatly speeded up as the objects under consideration areheated, particularly above 100 C., or are exposed to ultra-violet orother light rays. It has been observed that the deterioration inphysical properties is attended by a loss of sulfur dioxide orequivalent acid constituent from the reaction product, a loss which isgenerally proportional to the aforementioned deterioration. Accordingly,the rapidity with which a given product loses its acid constituent mayalso be taken as a measure of its stability, i. e., its resistance todeterioration with age, heating, and/or exposure to ultra-violet light.

It is an object of the present invention to provide a method forobtaining stable products of the type formed on the reaction of highmolecular weight, polyunsaturated compounds with inorganic acidifyingcompounds.

A more particular object is to provide filaments and like continuous,non-supported shapes composed of reaction products of the type discussedabove, yet which are highly stable and are characterized by a continuedhigh tensile strength and high degree of stretch prior to rupture, aswell as by a relatively small loss of acidifying compound, when saidfilaments or shapes are aged, heated and/or exposed to light rays.

The nature of still other objects will become apparent from thefollowing description of the invention.

It has been discovered that excellent resistance to deterioration withage, heat and/or exposure to ultra-violet and other light rays may beimparted to objects composed of the product formed on reacting highmolecular weight, polyunsaturated compounds with inorganic acidifyingcompounds by incorporating in said objects a nitrogen-containing organiccompound wherein a nitrogen atom is attached to a carbon atom which inturn is linked by a double bond to an oxygen, sulfur or nitrogen atomwhich does not form a part of a ring. The nitrogenous additives comingwithin the scope of the present invention are selected from the groupconsisting of carbamylsubstituted hydrocarbons, such as acetamide,stearamide, benzamide, acetanilide, n-valeramide, propionamide,n-caproamide, lauramide, N-methylacetamide, o-methylacetanilide, N-ethylbenzamide and N-phenylbenzamide; guanylsubstituted cyanamides andguanyl-substituted hydrocarbons, such as ethylamidine, acetamidine,cetylamidine and dicyandiamide (also known as cyanoguanidine) urethanessuch as urethane, acetylurethane, hedonal, ethylurethane, and theircorresponding thiourethane derivatives; dihydrocarbon-substitutedcarbodiimides such as diphenylcarbodiimide, diallylcarbodiimide andp,p-dimethyldiamino-diphenylcarbodiimide; and thiamides of carbodithioicacids such as zinc dimethyldithiocarbamate and thiuram disulfide, Ofthese various additives, the preferred compound for use in the presentinvention is dicyandiamide.

It also forms a feature of the present invention to stabilize theabove-described reaction products with both a nitrogenous additive ofthe type described in the preceding paragraph, as well as a compound ofthe type having the general formula:

wherein X is an oxygen or sulfur atom or the imine (NI-I) group, and R1,R2, R3, R4 represent hydrogen atoms, hydrocarbon radicals orpolarsubstituted hydrocarbon radicals. Compounds of this class,representative members of which are urea, thiourea, guanidine, N,N- andN,N'-diphenyl thiourea, and N,N- and N,N'-diphenyl thiourea and EN,N-and N,N'-diphenyl-quanidine, are disclosed in our co-pendingapplication, Serial No. 37,056, filed July 3, 1948, now Patent No.2,583,370, as useful stabilizers for the reaction products discussedabove. .When additives of the foregoing types are employed inconjunction with one another in sulfur dioxiderubbery polymer reactionproducts, there is observed not only an improved stability in thetreated reaction products, but also an improvement in the ability of thelatter to retain their improved stability under adverse environmentalconditions. A preferred combination is that of dicyandiamide with eitherurea or thiourea.

The stabilizer chosen, which, as noted above, may be one or a mixture ofseveral compounds, can be incorporated in the reaction product in one ormore of a number of different ways. Thus, for example, the stabilizermay be added to the solution of rubber or other polyunsaturated highmolecular weight reactant before the same is brought into reactiveengagement with the sulfur dioxide or other acidifying compoundemployed; alternatively, it may be added to the medium containing theacidifying compound. The practice of either of the foregoing methodsrequires that the stabilizer be soluble or at least dispersible in theliquid medium present, and preferably it should in no way interfere withthe desired re.- action between the respective unsaturated and acidiccompounds. Since some such interference may occur, particularly as theconcentration of stabilizer is increased or the more alkalinestabilizers are employed, the preferred manner of adding the stabilizeris to bring a solution thereof into contact with the already formedreaction product, preferably when the latter is still in the swollencondition due to its manner of production in the coagulating bath and/oras a result of subsequent washing steps. Thus, filaments produced byspinning a solution of peroxide activated rubber into anethanol-water-sulfur dioxide coagulating bath may thereafter be immersedin a solution of a stabilizer, as dicyandiamide in water and/or ethanol,for example, and left therein for any desired period of time. Otherappropriate solvents are acetone, propanol, butanol and methyl ethylketone. On being withdrawn from the stabilizer solution, the filamentsmay then be washed in the conventional manner (as with alcohol, water,dilute caustic or other liquid), stretched, dyed, or otherwise treated,following Which they may be dried and used. If desired, one or more ofsuch washing, Stretching and/or dyeing steps may intervene between theactual precipitation of the filaments in the coagulating bath and theirimmersion in the stabilizer solution, the filaments preferably remainingin the swollen condition during all said processing steps.Alternatively, the filaments may be treated in the dried (unswollen)condition with a solution of the desired stabilizing compound,preferably in a solvent such as benzene, ethyl alcohol, acetone or ethylacetate which acts to swell the filament, though non-filament swellingsolvents such as water may be employed in many cases. The stabilizersmay also be applied on or in the material to be stabilized otherwisethan by impregnation. Thus, the material may be contacted withdispersions of stabilizers or with an atmosphere which contains thestabilizers in the vaporous or atomized state. In the latter case asolution of the stabilizer may be atomized, if desired.

The concentration of stabilizer to employ, whether the same be added tothe unreacted materials, or is applied as a solution to the alreadyformed reaction product, is not critical. 'Ihus, good results areobtained with solutions containing from about 0.1 to 20% by weight of astabilizer, and some improvement can be effected even when using smallerquantities than 0.1%, particularly when more than one stabilizer beemployed. Preferably, however, the concentration of stabilizer should beat least 0.5% based on the entire weight of the solution, withconcentrations of more than seldom being juse tified in terms ofimproved results.

The period during which any given reaction product should be left in a,stabilizer solution will vary depending on a number of circumstances.Thus, in the. case of filaments and other small shapes the soakingperiod may be some? what. shorter than with articles of greater crosssection. Again, with more concentrated stabilize er solutions thesoaking period may be somewhat shortened. Another factor is the ease.with which 6. the reaction product is able to take up the stabilizersolution; thus, freshly formed, undried products (e. g., swollenfilaments) are considerably more receptive to the stabilizer solutionthan are objects which have already been dried and now must take upfresh quantities of solvent along with the dissolved stabilizer. Ingeneral, immersion periods of from 1 to 30' minutes are satisfactorywith swollen filaments, though soaking periods of one or more hours aredesirable when treating dried filaments. In all cases extension of thesoaking time is in no way harmful and in many cases proves ofconsiderable benefit. Where the stabilizer is added to the unreactedsolution of rubber or sulfur dioxide, for example, no modification needbe made in the nor mal process by which said compounds are reacted.

Of more importance than the duration of the treatment with stabilizersolution is the temperature thereof. It forms a feature of the presentinvention that improved results are obtained by employing a heatedstabilizer solution, by which term is meant a solution having atemperature of 50 C. or above, and preferably between 50 and 150 C. Theuse of such heated solutions serves in a measure to fix the stabilizerin the reaction product, thereby increasing its resistance to removalduring aging, or as a result of subsequent washing or other treatingsteps.

Still further improved results, notably as regards increased stabilityand resistance against age-deterioration following soap-washing and/oralkali-treating steps, are achieved by subjecting reaction productsalready impregnated with stabilizer compound to a treatment involvingheating said products in a gaseous environment such as air or nitrogen.The temperatures employed in this heating step may range from about 50to 250 0., though temperatures of from to C. are preferred. Effectivetreatments carried out in the latter temperature range normally takefrom to 4 or more hours, the relatively higher temperatures permittingeffective use of the shorter treating intervals. This dry heating stepmay be practiced with beneficial results no matter whether theimpregnation treatment referred to in the preceding paragraph beconducted at elevated temperatures or not, though as a general rule theone heating treatment re-..en-. forces the other. 7

It has also been found that improved results as regards fixation ofstabilizer may be obtained by utilizing a stabilizer compound such as.diallyl carbodiimide which contains one or more alkenyl or otherunsaturated, aliphatic groups. Such unsaturated stabilizing compoundsare preferably introduced into a solution of rubber or other highmolecular weight reactant prior to its reaction with the acidic compoundif the full effect of the stabilization treatment is to be obtained, forit seems quite probable that under these circumstances the stabilizerenters into, and chemically forms a part of, the final reaction product.

Still a third way of improving the bond between the reaction product andthe stabilizer is to treat the already stabilized product with analdehyde or isocyanate, the stabilizer present in the product reactingwith the aldehyde or isocyanate under these circumstances to form condet n. o oly-a di on. m unds ther of which are f such a cha ac s. t bewashed .out of the pr du t only with the reatest; dimculty;

The following examples illustrate the present invention in various ofits embodiments:

EXAMPLE I The material to be stabilized was a reaction product ofnatural rubber with sulfur dioxide in the form of dried filaments havinga sulfur content of 22% by weight, which material was produced byspinning a solution of natural rubber and tetralin hydroperoxide into asulfur dioxidecontaining coagulating bath, and thereafter stretching,washing, and drying the filaments in air at room temperature. Samples ofthese dried filaments were soaked in solutions of various stabilizers orcombinations of stabilizers for 4 hours, after which they were cursorilyrinsed with ethanol and dried in the open air, the concentration andtemperature of the various stabilizer solutions, as well as theiridentity, being indicated in Table I below. The stability of the sampleswas determined by measuring the quantity of sulfur dioxide liberated perunit of weight of the material on heating the same for two hours at 125C. in an air current. In the case of those tests reported in Table I,this loss of sulfur dioxide is expressed as the percentage of thequantity thereof lost in a blank test, i. e., with like filamentscontaining no stabilizer. As a matter of record, the actual quantity ofsulfur dioxide split ofi from the various samples during each two hourheating test period varied from about 1.5 to 3% by weight of the entiresample, this corresponding to loss in tensile strength of from 9 to 18%.

The stabilization operations summarized in Example I above involvedsoaking the dried filaments for 4 hours in the desired stabilizersolution. On repeating the soaking experiments with freshly prepared,swollen filaments it is found that equivalent results as regards freedomfrom loss of sulfur dioxide and general stability in the finally driedfilaments are obtained by soaking the filaments in stabilizer solutionsfor periods of from 1 to minutes.

EXAMPLE III This example illustrates the advantages achieved by soakingthe unstabilized filaments in hot solutions of the desired stabilizercompounds. In this case one lot of filaments of the kind described inExample I above was immersed for a period of 4 hours in a 2% solution ofdicyandiamide maintained at 20 C., whereas another lot of the filamentswas soaked in a similar solution maintained at 78 C. On being dried atroom temperature and then heated in air at 125 C., those filamentssoaked at 20 C. lost 0.14% by weight sulfur dioxide at the end of thefirst 30 minutes of heating, 0.22% after 60 minutes, and 0.28% afterminutes. In the case of the filaments soaked at 78 C., this loss wasreduced to 0.10% at the end of the first 30 minutes of heating, and0.16% and 0.22% at the end of 60 and 90 minute heating periods,respectively.

The above filaments, on being washed for four hours at 60 C. with a 0.4%soap solution, suffer an increase in the amount of sulfur dioxide lostin subsequent heating steps, though this increase is not as great in thecase of the filaments stabilized at 78 C., as it is with those whichwere treated at 28 C. In both cases, however, this increased sulfurdioxide loss following washing has been greatly minimized by subjectingthe stabilizer containing filaments to treatment in an air current at C.for periods of from one to two hours. The air treatment apparently actsto physically modify the filaments in a manner yet not understood, butit evidently prevents the physical removal of the stabilizer compoundsby the soap or other wash liquids.

EXAMPLE IV Synthetic rubber filaments containing approximately 20%sulfur dioxide were produced by spinning a solution of butadiene polymer(molecular weight approximately 50,000) activated with tetralinhydroperoxide into an ethanol-water coagulating bath containingdissolved sulfur dioxide. One lot of these filaments was stabilized bysoaking in an ethanol solution containing 2% by weight of dicyandiamideat 20 C. for a period of four hours whereas the other group was soakedin ethanol only. On drying both sets of filaments it was found thatthose impregnated with dicyandiamide had a resistance against thermaldeterioration which was approximately five times as great as that of theunstabilized filaments.

The invention claimed is:

1. The method of increasing the resistance to deterioration of a productformed on the reaction of natural rubber with sulfur dioxide, saidmethod comprising impregnating said product with a solution ofdicyandiamide.

2. The method of increasing the resistance to deterioration of a productformed on the reaction of natural rubber with sulfur dioxide, saidmethod comprising immersing said product in a heated solution ofdicyandiamide.

3. The method of increasing the resistance to deterioration with age ofa product formed on the reaction of natural rubber with sulfur dioxide,said method comprising impregnating said product with a solution ofdicyandiamide and thereafter heatin the product in a gaseousenvironment.

4. The method of claim 2 wherein there is added the step of heating theimpregnated product in a gaseous environment.

5. The method of increasing the resistance to deterioration of a productformed on the reaction of sulfur dioxide with a rubbery polymer of atleast one compound selected from the group consisting of conjugateddiolefins and chloroprene, in the presence of a peroxide activatingagent, these being the only reactants, said method comprisingimpregnating said product, while it is in a coagulated state and swollenwith solvent, with a solution of a stabilizer selected from the groupconsisting of guanyl-substituted cyanamides, guanyl-substitutedhydrocarbons, and di-hydrocarbon-substituted carbodiimides.

6. The method of claim 5 wherein the stabilizer is incorporated in saidproduct by immersing the latter in a heated solution of the stabilizer.

7. The method of claim wherein there is added the step of heating thestabilizer-containing product in a gaseous environment.

8. In a method wherein a solution containing a hydroperoxide and arubbery polymer of at least one compound selected from the groupconsisting of conjugated diolefins and chloroprene is spun into acoagulatin bath containing available sulfur dioxide, these being theonly reactants, whereby there is precipitated in the bath a filamentaryreaction product of the rubbery polymer and sulfur dioxide in the formof a continuous swollen filament which is then withdrawn from thecoagulating bath, the step comprising impregnating the still swollenfilament with a solution of a stabilizer selected from thegroupconsisting of guanyl-substituted cyanamides, guanyl-substitutedhydrocarbons and di-hydrocarbon-substituted carbodiimides.

9. A novel composition of matter comprising a reaction product of sulfurdioxide with a rubbery polymer of at least one compound selected fromthe group consistin of conjugated diolefins and chloroprene, these beingthe only reactants, which reaction product is impregnated with astabilizer selected from the group consisting of guanyl-substitutedcyanamides, guanyl-substituted hydrocarbons anddi-hydrocarbon-substituted carbodiimides.

10. A novel composition of matter comprising a reaction product ofsulfur dioxide with a rubbery polymer of at least one compound selectedfrom the group consisting of conjugated diolefins and chloroprene, thesebeing the only reactants, which reaction product is impregnated withdicyandiamide, as a stabilizer.

11. In a method wherein a solution containing a hydroperoxide andnatural rubber is spun into a coagulating bath containing availablesulfur dioxide, these being the only reactants, whereby there isprecipitated in the bath a filamentary reaction product of the rubberand sulfur dioxide in the form of a continuous swollen filament which isthen withdrawn from the coagulating bath, the step comprisingimpregnating the still swollen filament with a solution of a stabilizerselected from the group consisting of guanylsubstituted cyanamides,guanyl-substituted hydrocarbons and di-hydrocarbon-substituteclcarbodiimides.

12. A novel composition of matter comprising a reaction product ofsulfur dioxide with natural rubber, these being the only reactants,which reaction product is impregnated with dicyandiamide, as astabilizer.

13. The method of increasing the resistance to deterioration of aproduct formed on the reaction of sulfur dioxide with natural rubber,these being the only reactants, said method comprising impregnating saidproduct while it is in a coagulated state and swollen with solvent, witha solution of a stabilizer selected from the group consisting ofguanyl-substituted cyanamides, guanyl-substituted carbodiimides.

JOI-IAN MICHAEL GOPPEL. GOTTFRIED ERNST RUMSCHEIDT. JOHANNES THOMASHACKMANN.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,367,483 Cheyney Jan. 16, 1945 2,379,354 Hilton June 26, 19452,387,518 Lightbown Oct. 23, 1945 2,469,847 Rumscheidt May 10, 19492,583,370 Goppel et al Jan. 22, 1952 FOREIGN PATENTS Number Country Date593,036 Great Britain Oct. 7, 1947

9. A NOVEL COMPOSITION OF MATTER COMPRISING A REACTION PRODUCT OF SULFURDIOXIDE WITH A RUBBERY POLYMER OF AT LEAST ONE COMPOUND SELECTED FROMTHE GROUP CONSISTING OF CONJUGATED DIOLEFINS AND CHLOROPRENE, THESEBEING THE ONLY REACTANTS, WHICH REACTION PRODUCT IS IMPREGNATED WITH ASTABILIZER SELECTED FROM THE GROUP CONSISTING OF GUANYL-SUBSTITUTEDCYANAMIDES, GUANYL-SUBSTITUTED HYDROCARBONS ANDDI-HYDROCARBON-SUBSTITUTED CARBODIMIDES.